Siemens SIMATIC ET 200SP System Manual page 213

Commissioning
11.6 Operating modes of the CPU
No. Operating mode transitions
③
STOP →
STARTUP
④
STARTUP →
STOP
⑤
STARTUP →
RUN
⑥
RUN → STOP
212
The CPU switches to "STARTUP" mode
if:
The hardware configuration and
•
program blocks are consistent.
You set the CPU to "RUN" mode via
•
the programming device and the
mode switch in is RUN position.
Or
You set the mode switch from STOP
•
to RUN.
In the following cases, the CPU goes
from "STARTUP" to "STOP" mode
when:
The CPU detects an error during
•
startup.
You set the CPU to "STOP" via the
•
programming device or mode switch.
The CPU executes a STOP com-
•
mand in the Startup OB.
In the following cases, the CPU goes
from "STARTUP" to "RUN" mode when:
The CPU has initialized the PLC
•
tags.
The CPU has executed the startup
•
blocks successfully.
In the following cases, the CPU goes
from "RUN" back to "STOP" mode when:
The CPU detects an error which
•
prevents further work.
The CPU executes a STOP com-
•
mand in the user program.
You set the CPU to "STOP" via the
•
programming device or mode switch.
Effects
The CPU clears the non-retentive memory, and re-
sets the content of non-retentive DBs to the start
values of the load memory. Retentive memory and
retentive DB contents are retained.
The 500 newest entries in the diagnostics buffer are
retained.
These operating mode transitions have no effect on
data.
System Manual, 09/2019, A5E03576849-AJ
Distributed I/O system